Field of the Invention
The invention relates in general to a touch apparatus, and more particularly to an optical touch apparatus.
Description of the Related Art
As modern people are having more and more requirements of touch screen and the size of touch panel is getting larger and larger, the manufacturers, facing the pressure of high cost for manufacturing large-sized touch panels, gradually adopt optical touch technology. Furthermore, as the light-emitting diode (LED) element technology advances and is used in conjunction with the optical touch technology, optical touch products have gained more and more popularity and have replaced original resistive or capacitive touch products. In recent years, more and more large-sized touch panels such as desktop touch panels are using the optical touch technology.
In general, the optical touch panels currently available in the market can be divided into embedded type and plug-in type. The embedded type is featured in that most optical sensing modules are installed inside or on the rear side of the touch panel. The plug-in type is featured in that the optical sensing modules are installed at at least two corners of the touch panel. The plug-in type optical touch panels normally have two ways for sensing optical touch, that is, reflective type and light-shielding type. According to the light-shielding type, a sensing element is used to detect and determine the position of a dark spot generated by the light-shielding effect of the touch object. According to the reflective type, a sensing element is used to detect and determine the position of a bright spot generated by the reflection effect of the touch object.
In response to the requirements of briefing or teaching using large-sized display and touch control, single or multiple large-sized touch panels are used as primary displays and input interfaces such as the optical touch apparatus 110 with single touch panel or the optical touch apparatus 120 with double touch panels of FIG. 1. The operation principles are illustrated in FIG. 2A and FIG. 2B. FIG. 2A and FIG. 2B respectively illustrate a front view and a side view of a generally known plug-in optical touch apparatus 200. The touch panel 210 has two optical image capturing sensors 220, such as shooting lens, disposed thereon. The optical image capturing sensors 220 are electrically connected to the controller 230, and are respectively located at the top left corner and the top right corner of the touch panel 210. The touch panel 210 may include an LCD 210b and a protective glass 210a. The optical image capturing sensor 220 further has a light source 240, such as an infrared light light-emitting diode (IR LED).
When the user operates a touch reflective pen 250 on the protective glass 210a, the reflective material of the touch reflective pen 250 receives an infrared light from the light source 240, and reflects part of the infrared light. Both the two optical image capturing sensors 220 will receive the reflected light and generate a significant surge signal for the controller 230 to calculate the position of the touch reflective pen 250 by using the triangulation method.
The plug-in type optical touch apparatus, having simple structure and not interfering with or affecting the manufacturing process of liquid crystal display (LCD), is very suitable to be used in large-sized touch panel, and is more competitive than other touch panel in terms of material cost.
The large-sized touch panel is the main-stream of the optical touch panel, and is widely used in electronic products such as smart TV, interactive electronic billboard, and electronic whiteboard. The large-sized touch panel is ideal in the application fields such as office, education, advertisement and exhibition.
Most of the large-sized touch screens commonly seen in the market are the optical touch apparatus 110 of single touch panel or the optical touch apparatus 120 of double touch panels as indicated in FIG. 1. However, no matter the optical touch apparatus 110 or the optical touch apparatus 120 of the prior art, the size of the touch screen is fixed and cannot be flexibly adjusted to meet the users' needs, the commonality is poor and the application fields of optical touch products are restricted. Therefore, how to resolve the abovementioned needs and provide an optical touch one machine having versatile functions, which largely increases procurement cost and increases product competiveness, is a prominent task for the optical touch industries.